A control method, system, device, medium and product for a parallel power supply system

Abstract

The present application relates to a control method, system, equipment, medium and product for a parallel power supply system. In the present application, each controller controls the amplitude of the output voltage of the inverter to be maintained at a second preset voltage value within a preset time period, and then adjusts or maintains the phase of the modulation wave of the inverter according to the first real-time output voltage and the first real-time bridge arm current until the timing value of the timer reaches the preset time period, so that the phase of the output voltage of each inverter is the same when the preset time period is reached, and then synchronously adjusts the amplitude of the output voltage of each inverter to the rated voltage value according to the second real-time output voltage and the rated voltage value, so that the synchronous startup of each inverter in the parallel power supply system can be achieved without network communication between the controllers, which can effectively reduce the complexity of the control system of the parallel power supply system and the dependence of the control system of the parallel power supply system on the network.

Description

Technical Field

[0001] The present application belongs to the field of converter power supply technology, and in particular relates to a control method, system, equipment, medium and product for a parallel power supply system. Background Art

[0002] In rail transit, a power supply system consisting of multiple inverters connected in parallel to the AC bus is usually used to power the loads in the train. This power supply method is crucial to ensuring the stability and safety of train operation.

[0003] Currently, multiple inverters in a parallel power supply system are individually controlled by multiple controllers. To avoid conflicts during the startup process of multiple inverters, multiple controllers need to communicate through a network to control the startup of multiple inverters one by one. However, this method, on the one hand, increases the complexity of the control system of the parallel power supply system and makes the control system of the parallel power supply system heavily dependent on the network; on the other hand, since the inverters are started one by one, in order to avoid overloading the inverter that is started first, there is a capacity limit on the load directly connected to the AC bus. Summary of the Invention

[0004] The purpose of this application is to provide a control method, system, equipment, medium and product for a parallel power supply system; the control method, system, equipment, medium and product for a parallel power supply system provided in this application can effectively reduce the complexity of the control system of the parallel power supply system, can effectively reduce the dependence of the control system of the parallel power supply system on the network, and can effectively improve the starting capability of the parallel power supply system with direct-hung loads.

[0005] The technical solutions provided in this application are as follows:

[0006] A control method for a parallel power supply system is applied to the control system of the parallel power supply system, wherein the parallel power supply system includes multiple inverters, multiple contactors, and an AC busbar. The multiple inverters are connected to the AC busbar in parallel via the multiple contactors. A voltage sensor is provided between each contactor and the AC busbar, and a current sensor is provided on the bridge arm of each inverter. The control system of the parallel power supply system includes multiple controllers, each controller is connected to each inverter, each contactor, each voltage sensor, and each current sensor in a one-to-one correspondence. The method performed by each controller includes:

[0007] Acquiring a first bus voltage collected by the voltage sensor;

[0008] When the acquired amplitude of the first bus voltage is less than the first preset voltage value, controlling the contactor to close, controlling the timer to start timing, and controlling the amplitude of the output voltage of the inverter to remain at a second preset voltage value within a preset time period;

[0009] Acquire a first real-time output voltage of the inverter collected by the voltage sensor, and a first real-time bridge arm current of the inverter collected by the current sensor;

[0010] Adjusting or maintaining the phase of the modulation wave of the inverter according to the first real-time output voltage and the first real-time bridge arm current until the timing value of the timer reaches the preset duration;

[0011] Acquiring a second real-time output voltage of the inverter collected by the voltage sensor;

[0012] According to the second real-time output voltage and the rated voltage value, the amplitude of the modulation wave of the inverter is adjusted until the amplitude of the output voltage of the inverter is equal to the rated voltage value.

[0013] Optionally, adjusting or maintaining the phase of the modulation wave of the inverter according to the first real-time output voltage and the first real-time bridge arm current until the timing value of the timer reaches the preset duration includes:

[0014] Obtaining the active power of the inverter according to the first real-time output voltage, the first real-time bridge arm current and an active power calculation formula;

[0015] According to the active power, the phase of the modulation wave of the inverter is adjusted or maintained until the timing value of the timer reaches the preset time length.

[0016] Optionally, the method executed by each of the controllers further includes:

[0017] Acquire a third real-time output voltage of the inverter acquired by the voltage sensor, and a second real-time bridge arm current of the inverter acquired by the current sensor;

[0018] Obtaining a voltage error according to the third real-time output voltage and the rated voltage value;

[0019] Obtaining the reactive power of the inverter according to the third real-time output voltage, the second real-time bridge arm current and a reactive power calculation formula;

[0020] The amplitude of the modulation wave of the inverter is controlled according to the voltage error and the reactive power.

[0021] Optionally, before obtaining the first bus voltage collected by the voltage sensor, the method further includes:

[0022] The first controller controls the corresponding contactor to close, obtains the second bus voltage collected by the corresponding voltage sensor, and samples the obtained second bus voltage to obtain a first sampling value;

[0023] The remaining controllers obtain a third bus voltage collected by a corresponding voltage sensor, sample the third bus voltage, and obtain a second sampling value. If the second sampling value is not equal to the first sampling value, adjust a voltage sampling coefficient so that a real-time sampling value obtained based on the adjusted voltage sampling coefficient is equal to the first sampling value.

[0024] The first controller controls the corresponding contactor to open.

[0025] Optionally, the method executed by each of the controllers further includes:

[0026] Acquire a fourth real-time output voltage of the inverter collected by the voltage sensor, and a third real-time bridge arm current of the inverter collected by the current sensor;

[0027] Obtaining a phase and an amplitude of a specific subharmonic voltage and an amplitude of a specific subharmonic current according to the fourth real-time output voltage and the third real-time bridge arm current;

[0028] Obtaining a harmonic suppression calculation amplitude according to the amplitude of the specific subharmonic voltage and a preset harmonic amplitude;

[0029] Determine whether the amplitude of the specific subharmonic current is greater than or equal to a preset current threshold; if not, use the harmonic suppression calculated amplitude as the target harmonic suppression amplitude; if so, use the current harmonic suppression amplitude as the target harmonic suppression amplitude;

[0030] A harmonic suppression wave is obtained according to the phase of the specific subharmonic voltage and the target harmonic suppression amplitude, and a modulation wave of the inverter is adjusted according to the harmonic suppression wave.

[0031] The present application also provides a control system for a parallel power supply system, the parallel power supply system comprising a plurality of inverters, a plurality of contactors, and an AC busbar, wherein the plurality of inverters are connected in parallel to the AC busbar via the plurality of contactors, a voltage sensor is provided between each contactor and the AC busbar, and a current sensor is provided on a bridge arm of each inverter, the control system for the parallel power supply system comprising a plurality of controllers, each of the controllers being connected in a one-to-one correspondence with each of the inverters, each of the contactors, each of the voltage sensors, and each of the current sensors, and each of the controllers being configured to:

[0032] Acquiring a first bus voltage collected by the voltage sensor;

[0033] When the acquired amplitude of the first bus voltage is less than the first preset voltage value, controlling the contactor to close, controlling the timer to start timing, and controlling the amplitude of the output voltage of the inverter to remain at a second preset voltage value within a preset time period;

[0034] Acquire a first real-time output voltage of the inverter acquired by the voltage sensor, and a first real-time bridge arm current of the inverter acquired by the current sensor;

[0035] Adjusting or maintaining the phase of the modulation wave of the inverter according to the first real-time output voltage and the first real-time bridge arm current until the timing value of the timer reaches the preset duration;

[0036] Acquiring a second real-time output voltage of the inverter collected by the voltage sensor;

[0037] According to the second real-time output voltage and the rated voltage value, the amplitude of the modulation wave of the inverter is adjusted until the amplitude of the output voltage of the inverter is equal to the rated voltage value.

[0038] Optionally, each of the controllers, when adjusting or maintaining the phase of the modulation wave of the inverter according to the first real-time output voltage and the first real-time bridge arm current until the timing value of the timer reaches the preset duration, is specifically configured to:

[0039] Obtaining the active power of the inverter according to the first real-time output voltage, the first real-time bridge arm current and an active power calculation formula;

[0040] According to the active power, the phase of the modulation wave of the inverter is adjusted or maintained until the timing value of the timer reaches the preset time length.

[0041] Optionally, each of the controllers is further configured to:

[0042] Acquire a third real-time output voltage of the inverter collected by the voltage sensor, and a second real-time bridge arm current of the inverter collected by the current sensor;

[0043] Obtaining a voltage error according to the third real-time output voltage and the rated voltage value;

[0044] Obtaining the reactive power of the inverter according to the third real-time output voltage, the second real-time bridge arm current and a reactive power calculation formula;

[0045] The amplitude of the modulation wave of the inverter is controlled according to the voltage error and the reactive power.

[0046] Optionally,

[0047] The first controller is further configured to control the corresponding contactor to close, obtain the second bus voltage collected by the corresponding voltage sensor, and sample the obtained second bus voltage to obtain a first sampled value;

[0048] The remaining controllers are further configured to obtain a third bus voltage collected by a corresponding voltage sensor, sample the third bus voltage to obtain a second sampling value, and if the second sampling value is not equal to the first sampling value, adjust a voltage sampling coefficient so that a real-time sampling value obtained based on the adjusted voltage sampling coefficient is equal to the first sampling value;

[0049] The first controller is also used to control the corresponding contactor to disconnect.

[0050] Optionally, each of the controllers is further configured to:

[0051] Acquire a fourth real-time output voltage of the inverter collected by the voltage sensor, and a third real-time bridge arm current of the inverter collected by the current sensor;

[0052] Obtaining a phase and an amplitude of a specific subharmonic voltage and an amplitude of a specific subharmonic current according to the fourth real-time output voltage and the third real-time bridge arm current;

[0053] Obtaining a harmonic suppression calculation amplitude according to the amplitude of the specific subharmonic voltage and a preset harmonic amplitude;

[0054] Determine whether the amplitude of the specific subharmonic current is greater than or equal to a preset current threshold; if not, use the harmonic suppression calculated amplitude as the target harmonic suppression amplitude; if so, use the current harmonic suppression amplitude as the target harmonic suppression amplitude;

[0055] A harmonic suppression wave is obtained according to the phase of the specific subharmonic voltage and the target harmonic suppression amplitude, and a modulation wave of the inverter is adjusted according to the harmonic suppression wave.

[0056] The present application also provides an electronic device, comprising: a processor, a memory, and a communication bus;

[0057] The communication bus is used to realize the connection and communication between the processor and the memory;

[0058] The processor is used to execute the control processing program of the parallel power supply system stored in the memory to implement the steps of the control method of the parallel power supply system as described in any one of the above items.

[0059] The present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are loaded and executed by a processor, the steps of the control method of the parallel power supply system as described in any one of the above items are implemented.

[0060] The present application also provides a computer program product, comprising computer executable instructions, which, when loaded and executed by a processor, implement the steps of the control method for the parallel power supply system as described in any one of the above items.

[0061] Compared with the prior art, the present application provides a control method, system, device, medium and product for a parallel power supply system. Each controller obtains a first bus voltage collected by a voltage sensor. When the amplitude of the obtained first bus voltage is less than a first preset voltage value, it controls the contactor to close, controls the timer to start timing, and controls the amplitude of the output voltage of the inverter to be maintained at a second preset voltage value within a preset time. Then, the first real-time output voltage of the inverter collected by the voltage sensor and the first real-time bridge arm current of the inverter collected by the current sensor are obtained. According to the first real-time output voltage and the first real-time bridge arm current, the phase of the modulation wave of the inverter is adjusted or maintained until the timing value of the timer reaches the preset time, so that when the timing value of the timer reaches the preset time, the phase of the output voltage of each inverter is the same. Then, the second real-time output voltage of the inverter collected by the voltage sensor is obtained. According to the second real-time output voltage and the rated voltage value, the amplitude of the modulation wave of the inverter is adjusted until the amplitude of the output voltage of the inverter is equal to the rated voltage. A constant voltage value is set so that the amplitude of the output voltage of each inverter is the same. In the present application, when the amplitude of the first bus voltage obtained is less than the first preset voltage value, each controller controls the contactor to close, controls the timer to start timing, and controls the amplitude of the output voltage of the inverter to be maintained at a second preset voltage value within the preset time. Then, according to the first real-time output voltage and the first real-time bridge arm current, the phase of the modulation wave of the inverter is adjusted or maintained until the timing value of the timer reaches the preset time, so that the phase of the output voltage of each inverter is the same when the preset time is reached. Then, according to the second real-time output voltage and the rated voltage value, the amplitude of the output voltage of each inverter is synchronously adjusted to the rated voltage value, so that there is no need for network communication between the controllers to realize the synchronous startup of each inverter in the parallel power supply system, which can effectively reduce the complexity of the control system of the parallel power supply system, can effectively reduce the dependence of the control system of the parallel power supply system on the network, and can effectively improve the startup capability of the parallel power supply system with direct-hook load. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0063] Figure 1 This is a flow chart of a control method for a parallel power supply system disclosed in an embodiment of the present application;

[0064] Figure 2 This is a structural block diagram of the parallel power supply system disclosed in the embodiment of this application;

[0065] Figure 3 This is a structural block diagram of a control system of a parallel power supply system disclosed in an embodiment of the present application;

[0066] Figure 4 A schematic diagram of connecting multiple controllers disclosed in an embodiment of the present application with multiple inverters, multiple contactors, multiple voltage sensors, and multiple current sensors;

[0067] Figure 5 This is a schematic structural diagram of an electronic device disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0068] In order to help those skilled in the art better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of this application.

[0069] It should be noted that when an element is referred to as being “fixed on” or “set on” another element, it can be directly on the other element or indirectly set on the other element; when an element is referred to as being “connected to” another element, it can be directly connected to the other element or indirectly connected to the other element.

[0070] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0071] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout the description of this application, "plurality" or "several" means two or more, unless otherwise specifically defined.

[0072] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions under which this application can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in this application without affecting the efficacy and purpose that can be achieved by this application.

[0073] like Figure 1 As shown, the embodiment of the present application provides a control method for a parallel power supply system, which is applied to a control system of a parallel power supply system, such as Figure 2 As shown, the parallel power supply system includes multiple inverters 100, multiple contactors 200 and AC busbars. Multiple inverters 100 are connected to the AC busbars in parallel through multiple contactors 200. A voltage sensor 300 is provided between each contactor 200 and the AC busbar. A current sensor 400 is provided on the bridge arm of each inverter 100. The voltage sensor 300 and the current sensor 400 are not shown in the attached figure. Figure 2 It is displayed in Figure 3 As shown, the control system of the parallel power supply system includes multiple controllers 500, such as Figure 4 As shown, each controller 500 is connected to each inverter 100, each contactor 200, each voltage sensor 300 and each current sensor 400 in a one-to-one correspondence, and the method executed by each controller includes:

[0074] S11, obtaining a first bus voltage collected by a voltage sensor;

[0075] S12. When the acquired amplitude of the first bus voltage is less than the first preset voltage value, controlling the contactor to close, controlling the timer to start timing, and controlling the amplitude of the output voltage of the inverter to remain at a second preset voltage value within a preset time period;

[0076] In this embodiment, the first preset voltage value and the second preset voltage value are preset voltage values, and the preset duration is a preset duration. The first preset voltage value may be 50V, the second preset voltage value may be 10V or 20V, and the preset duration may be 50ms. When the amplitude of the obtained first bus voltage is less than the first preset voltage value, it indicates that there is no high voltage on the bus at this time, that is, other inverters have not yet been connected to the bus. The contactor is controlled to close so that the inverter is connected to the bus, and the timer inside the controller is controlled to start timing. Then, the amplitude of the inverter's output voltage is controlled to remain at a smaller, constant second preset voltage value within the preset duration. If the amplitude of the obtained first bus voltage is greater than or equal to the first preset voltage value, the inverter can be controlled to phase-lock output.

[0077] S13, acquiring a first real-time output voltage of the inverter acquired by a voltage sensor, and a first real-time bridge arm current of the inverter acquired by a current sensor;

[0078] S14. Adjust or maintain the phase of the modulation wave of the inverter according to the first real-time output voltage and the first real-time bridge arm current until the timing value of the timer reaches a preset duration;

[0079] In this embodiment, the active power of the inverter can be obtained based on the first real-time output voltage, the first real-time bridge arm current and the active power calculation formula, and then the phase of the modulation wave of the inverter is adjusted or maintained based on the active power until the timing value of the timer reaches the preset duration, so that when the timing value of the timer reaches the preset duration, the phase of the output voltage of each inverter is the same.

[0080] S15. Acquire a second real-time output voltage of the inverter collected by a voltage sensor;

[0081] S16. Adjust the amplitude of the modulation wave of the inverter according to the second real-time output voltage and the rated voltage value until the amplitude of the output voltage of the inverter is equal to the rated voltage value.

[0082] In this embodiment, the rated voltage value can be 380V, and the amplitude of the modulation wave of the inverter can be increased according to the second real-time output voltage, the rated voltage value and the pre-set slope until the amplitude of the output voltage of the inverter is equal to the rated voltage value. During the increase of the amplitude of the output voltage of the inverter, if the amplitude of the output voltage of the inverter suddenly becomes too large due to external interference, current limiting will be triggered to limit the excessive amplitude, so that the inverter maintains the same amplitude or a similar amplitude increase during startup.

[0083] Compared with the prior art, the present application provides a control method, system, device, medium and product for a parallel power supply system. Each controller obtains a first bus voltage collected by a voltage sensor. When the amplitude of the obtained first bus voltage is less than a first preset voltage value, it controls the contactor to close, controls the timer to start timing, and controls the amplitude of the output voltage of the inverter to be maintained at a second preset voltage value within a preset time. Then, the first real-time output voltage of the inverter collected by the voltage sensor and the first real-time bridge arm current of the inverter collected by the current sensor are obtained. According to the first real-time output voltage and the first real-time bridge arm current, the phase of the modulation wave of the inverter is adjusted or maintained until the timing value of the timer reaches the preset time, so that when the timing value of the timer reaches the preset time, the phase of the output voltage of each inverter is the same. Then, the second real-time output voltage of the inverter collected by the voltage sensor is obtained. According to the second real-time output voltage and the rated voltage value, the amplitude of the modulation wave of the inverter is adjusted until the amplitude of the output voltage of the inverter is Equal to the rated voltage value, so that the amplitude of the output voltage of each inverter is the same. When the amplitude of the first bus voltage obtained by each controller is less than the first preset voltage value, the contactor is controlled to close, and the timer is controlled to start timing, and the amplitude of the output voltage of the inverter is controlled to be maintained at the second preset voltage value within the preset time. Then, according to the first real-time output voltage and the first real-time bridge arm current, the phase of the modulation wave of the inverter is adjusted or maintained until the timing value of the timer reaches the preset time, so that the phase of the output voltage of each inverter is the same when the preset time is reached, and then according to the second real-time output voltage and the rated voltage value, the amplitude of the output voltage of each inverter is synchronously adjusted to the rated voltage value, so that there is no need for network communication between the controllers, and the synchronous startup of each inverter in the parallel power supply system can be achieved, which can effectively reduce the complexity of the control system of the parallel power supply system, can effectively reduce the dependence of the control system of the parallel power supply system on the network, and can effectively improve the startup capability of the parallel power supply system with direct-hook load.

[0084] As an implementation manner, in the embodiment of the present application, step S14 includes:

[0085] S141. Obtain active power of the inverter according to the first real-time output voltage, the first real-time bridge arm current, and the active power calculation formula;

[0086] In this embodiment, the first real-time output voltage is a three-phase voltage, and the first real-time output voltage includes a first real-time output a-phase voltage, a first real-time output b-phase voltage, and a first real-time output c-phase voltage, specifically:

[0087] ;

[0088] ;

[0089] ;

[0090] in, is the first real-time output a-phase voltage, is the first real-time output b-phase voltage, The first real-time output C-phase voltage.

[0091] The first real-time bridge arm current is a three-phase current, and the first real-time bridge arm current includes a first real-time bridge arm a-phase current, a first real-time bridge arm b-phase current, and a first real-time bridge arm c-phase current, specifically:

[0092] ;

[0093] ;

[0094] ;

[0095] in, is the first real-time bridge arm a phase current, is the first real-time bridge arm b phase current, is the first real-time bridge arm c-phase current.

[0096] The effective value U of the first real-time output voltage, the effective value I of the first real-time bridge arm current, and the phase difference φ between the phase of the first real-time output voltage and the phase of the first real-time bridge arm current can be substituted into the active power calculation formula to calculate the active power of the inverter. The specific active power calculation formula is:

[0097] P = UIcosφ;

[0098] Wherein, P is the active power of the inverter, U is the effective value of the first real-time output voltage, I is the effective value of the first real-time bridge arm current, and φ is the phase difference between the phase of the first real-time output voltage and the phase of the first real-time bridge arm current.

[0099] S142. Adjust or maintain the phase of the modulation wave of the inverter according to the active power until the timing value of the timer reaches a preset duration.

[0100] In this embodiment, one or more inverters with active power greater than 0 adjust the phase of the modulation wave of the inverter at a corresponding change rate according to the corresponding active power P. That is, the phase of the modulation wave of each inverter with active power greater than 0 will change at different rates according to the active power P. One or more inverters with active power of 0 will maintain the phase of the modulation wave of the inverter, so that when the timing value of the timer reaches the preset time length, the active power of each inverter is 0, the phase of the modulation wave of each inverter is the same, the phase change is stopped, and the phase synchronization is completed.

[0101] Specifically, for one or more inverters with active power greater than 0, the corresponding active power can be substituted into the preset formula of the initial phase of the modulation wave to calculate the adjusted phase of the modulation wave of the inverter. The preset formula is as follows:

[0102] In this embodiment, the preset formula may be specifically:

[0103] ;

[0104] in, is the adjusted phase of the inverter modulation wave, is the initial phase of the modulation wave of the inverter, k is a constant, and P is the active power of the inverter;

[0105] k can be 0.001. The phase of the modulation wave of each inverter with active power greater than 0 will be changed at the corresponding phase adjustment rate using the constant k and the integral of the corresponding active power P. One or more inverters with active power of 0 will maintain the phase of the modulation wave of the inverter so that when the timer reaches the preset time, the active power of each inverter is 0 and the phase of the modulation wave of each inverter is the same.

[0106] As an implementation manner, in the embodiment of the present application, the method executed by each controller further includes:

[0107] S21, acquiring a third real-time output voltage of the inverter acquired by a voltage sensor, and a second real-time bridge arm current of the inverter acquired by a current sensor;

[0108] S22. Obtain a voltage error according to the third real-time output voltage and the rated voltage value;

[0109] In this embodiment, the collected third real-time output voltage may be subtracted from the rated voltage value to obtain a voltage error.

[0110] S23, obtaining the reactive power of the inverter according to the third real-time output voltage, the second real-time bridge arm current and the reactive power calculation formula;

[0111] In this embodiment, the effective value of the third real-time output voltage, the effective value of the second real-time bridge arm current, the phase difference between the phase of the third real-time output voltage and the phase of the second real-time bridge arm current can be substituted into the reactive power calculation formula to calculate the reactive power of the inverter. Since the reactive power calculation formula is an existing calculation formula, it will not be repeated here.

[0112] S24. Control the amplitude of the modulation wave of the inverter according to the voltage error and reactive power.

[0113] In this embodiment, since the output reactive power of the inverter is proportional to the amplitude of the output voltage, and the amplitude of the output voltage of the inverter is proportional to the amplitude of the modulation wave of the inverter, the difference in the modulation wave amplitude of multiple inverters can be reflected by the difference in reactive power.

[0114] Rated output voltage of each inverter Constant 380V, by subtracting the rated voltage value and the third real-time output voltage Subtract the two to get the voltage error, and give the voltage error signal to the adaptive voltage controller. Through the error weighted control of the controller, the Ke and Kc coefficients of the controller will be adjusted in real time according to the reactive power of the current inverter to control the amplitude of the modulation wave of the inverter, so that the amplitude of the bus voltage output by multiple inverters in parallel can be dynamically kept constant at the rated voltage value or within the acceptable error range of the rated voltage value.

[0115] Specifically, the output voltage in the third real time Lower than rated voltage When the inverter with smaller reactive power among multiple inverters is adaptively adjusted, Ke and Kc will be larger, giving a higher target voltage; in the third real-time output voltage Higher than rated voltage When adaptively adjusting the reactive power of the inverter with smaller reactive power among the multiple inverters, Ke and Kc will be smaller, giving a higher target voltage. This allows the amplitude of the bus voltage output by the multiple inverters connected in parallel to be dynamically constant at the rated voltage value or within an acceptable error range of the rated voltage value (e.g., the bus voltage error is within ±1% of the rated voltage value) after the amplitude of the modulation wave of each inverter in the multiple inverters is dynamically adjusted. This effectively improves the accuracy of the output voltage of the parallel power supply of the inverters.

[0116] As an implementation manner, in the embodiment of the present application, before step S11, the method further includes:

[0117] S31. The first controller controls the corresponding contactor to close, obtains the second bus voltage collected by the corresponding voltage sensor, and samples the obtained second bus voltage to obtain a first sampling value;

[0118] In this embodiment, the first controller controls the corresponding connected contactor to close, obtains the second bus voltage collected by the corresponding connected voltage sensor, samples the obtained second bus voltage, and obtains a first sampled value.

[0119] S32. The remaining controllers obtain the third bus voltage collected by the corresponding voltage sensor and sample the third bus voltage to obtain a second sampling value. If the second sampling value is not equal to the first sampling value, adjust the voltage sampling coefficient so that the real-time sampling value obtained based on the adjusted voltage sampling coefficient is equal to the first sampling value.

[0120] In this embodiment, the multiple controllers may be N controllers, where N is a positive integer greater than 1. The N-1 controllers other than the first controller respectively obtain N-1 third bus voltages collected by the corresponding connected voltage sensors, and sample the N-1 third bus voltages to obtain N-1 second sampling values. If one or more of the second sampling values ​​are not equal to the first sampling value, the one or more voltage sampling coefficients corresponding to the one or more second sampling values ​​are adjusted so that the one or more real-time sampling values ​​obtained based on the adjusted one or more voltage sampling coefficients are equal to the first sampling value, so that each voltage sampling coefficient can be effectively corrected, which can reduce the risk of circulating current and uneven power distribution in the system due to differences in device parameters or sensor accuracy of each inverter.

[0121] S33. The first controller controls the corresponding contactor to disconnect.

[0122] As an implementation manner, in the embodiment of the present application, the method executed by each controller further includes:

[0123] S41, acquiring a fourth real-time output voltage of the inverter acquired by a voltage sensor, and a third real-time bridge arm current of the inverter acquired by a current sensor;

[0124] S42. Obtaining a phase and amplitude of a specific subharmonic voltage and an amplitude of a specific subharmonic current according to the fourth real-time output voltage and the third real-time bridge arm current;

[0125] In this embodiment, specific subharmonics can be extracted from the fourth real-time output voltage to obtain the phase and amplitude of the specific subharmonic voltage, and specific subharmonics can be extracted from the third real-time bridge arm current to obtain the amplitude of the specific subharmonic current. The specific subharmonic can be the fifth harmonic or the seventh harmonic.

[0126] S43. Obtaining a harmonic suppression calculation amplitude according to the amplitude of the specific subharmonic voltage and a preset harmonic amplitude;

[0127] In this embodiment, the preset harmonic amplitude is a pre-set harmonic amplitude, which may be 0. The harmonic suppression calculation amplitude may be obtained by calculation based on the amplitude of a specific subharmonic voltage and the preset harmonic amplitude.

[0128] S44. Determine whether the amplitude of the specific subharmonic current is greater than or equal to a preset current threshold; if not, use the harmonic suppression calculated amplitude as the target harmonic suppression amplitude; if so, use the current harmonic suppression amplitude as the target harmonic suppression amplitude;

[0129] In this embodiment, the preset current threshold can be a pre-set current threshold to determine whether the amplitude of a specific subharmonic current is greater than or equal to the preset current threshold. If the amplitude of the specific subharmonic current is less than the preset current threshold, the harmonic suppression calculation amplitude is used as the target harmonic suppression amplitude. If the amplitude of the specific subharmonic current is greater than or equal to the preset current threshold, the current harmonic suppression amplitude is used as the target harmonic suppression amplitude.

[0130] S45 . Obtain a harmonic suppression wave according to the phase of the specific subharmonic voltage and the target harmonic suppression amplitude, and adjust the modulation wave of the inverter according to the harmonic suppression wave.

[0131] In this embodiment, a harmonic suppression wave is obtained based on the phase of a specific subharmonic voltage and a target harmonic suppression amplitude, and the modulation wave of the inverter is adjusted based on the harmonic suppression wave, which can effectively suppress harmonics and effectively reduce the risk of inverter failure due to harmonic problems.

[0132] The present application also provides a control system for a parallel power supply system, such as Figure 2 As shown, the parallel power supply system includes multiple inverters 100, multiple contactors 200 and AC busbars. Multiple inverters 100 are connected to the AC busbars in parallel through multiple contactors 200. A voltage sensor 300 is provided between each contactor 200 and the AC busbar. A current sensor 400 is provided on the bridge arm of each inverter 100. The voltage sensor 300 and the current sensor 400 are not shown in the attached figure. Figure 2 It is displayed in Figure 3 As shown, the control system of the parallel power supply system includes multiple controllers 500, such as Figure 4 As shown, each controller 500 is connected to each inverter 100, each contactor 200, each voltage sensor 300 and each current sensor 400 in a one-to-one correspondence. Each controller is used to:

[0133] Obtaining a first bus voltage collected by a voltage sensor;

[0134] When the acquired amplitude of the first bus voltage is less than the first preset voltage value, the contactor is controlled to close, the timer is controlled to start timing, and the amplitude of the output voltage of the inverter is controlled to be maintained at the second preset voltage value within a preset time period;

[0135] Acquire a first real-time output voltage of the inverter collected by a voltage sensor, and a first real-time bridge arm current of the inverter collected by a current sensor;

[0136] Adjusting or maintaining the phase of the modulation wave of the inverter according to the first real-time output voltage and the first real-time bridge arm current until the timing value of the timer reaches a preset duration;

[0137] Acquiring a second real-time output voltage of the inverter collected by a voltage sensor;

[0138] According to the second real-time output voltage and the rated voltage value, the amplitude of the modulation wave of the inverter is adjusted until the amplitude of the output voltage of the inverter is equal to the rated voltage value.

[0139] As an implementation manner, in the embodiment of the present application, each controller, when executing the adjustment or maintenance of the phase of the modulation wave of the inverter according to the first real-time output voltage and the first real-time bridge arm current until the timing value of the timer reaches a preset duration, is specifically configured to:

[0140] Obtaining the active power of the inverter according to the first real-time output voltage, the first real-time bridge arm current and the active power calculation formula;

[0141] According to the active power, the phase of the modulation wave of the inverter is adjusted or maintained until the timing value of the timer reaches the preset duration.

[0142] As an implementation manner, in the embodiment of the present application, each controller is further configured to:

[0143] Acquire a third real-time output voltage of the inverter collected by a voltage sensor, and a second real-time bridge arm current of the inverter collected by a current sensor;

[0144] Obtaining a voltage error according to the third real-time output voltage and the rated voltage value;

[0145] Obtaining the reactive power of the inverter according to the third real-time output voltage, the second real-time bridge arm current and the reactive power calculation formula;

[0146] The amplitude of the modulation wave of the inverter is controlled according to the voltage error and reactive power.

[0147] As an implementation method, in the examples of this application,

[0148] The first controller is further configured to control the corresponding contactor to close, obtain the second bus voltage collected by the corresponding voltage sensor, and sample the obtained second bus voltage to obtain a first sampled value;

[0149] The remaining controllers are further configured to obtain a third bus voltage collected by a corresponding voltage sensor, sample the third bus voltage to obtain a second sampling value, and if the second sampling value is not equal to the first sampling value, adjust a voltage sampling coefficient so that a real-time sampling value obtained based on the adjusted voltage sampling coefficient is equal to the first sampling value;

[0150] The first controller is also used to control the corresponding contactor to disconnect.

[0151] As an implementation manner, in the embodiment of the present application, each controller is further configured to:

[0152] Acquire a fourth real-time output voltage of the inverter collected by a voltage sensor, and a third real-time bridge arm current of the inverter collected by a current sensor;

[0153] Obtaining the phase and amplitude of a specific subharmonic voltage and the amplitude of a specific subharmonic current according to the fourth real-time output voltage and the third real-time bridge arm current;

[0154] Obtaining a harmonic suppression calculation amplitude based on the amplitude of a specific subharmonic voltage and a preset harmonic amplitude;

[0155] Determine whether the amplitude of the specific subharmonic current is greater than or equal to a preset current threshold; if not, use the harmonic suppression calculated amplitude as the target harmonic suppression amplitude; if so, use the current harmonic suppression amplitude as the target harmonic suppression amplitude;

[0156] A harmonic suppression wave is obtained according to the phase of the specific subharmonic voltage and the target harmonic suppression amplitude, and the modulation wave of the inverter is adjusted according to the harmonic suppression wave.

[0157] like Figure 5 As shown, an embodiment of the present application further provides an electronic device, including: a processor 600, a memory 700 and a communication bus 800;

[0158] The communication bus 800 is used to realize the connection and communication between the processor 600 and the memory 700;

[0159] The processor 600 is configured to execute the control processing program for the parallel power supply system stored in the memory 700 to implement the steps of any of the above-mentioned control methods for the parallel power supply system.

[0160] An embodiment of the present application also provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are loaded and executed by a processor, the steps of any of the above-mentioned control methods for parallel power supply systems are implemented.

[0161] An embodiment of the present application also provides a computer program product, including computer-executable instructions. When the computer-executable instructions are loaded and executed by a processor, the steps of any of the above-mentioned control methods for parallel power supply systems are implemented.

[0162] It should be understood that the use of "system," "device," "unit," and / or "module" in this application is merely a method for distinguishing different components, elements, parts, portions, or assemblies at different levels. However, if other terms can achieve the same purpose, the terms may be replaced by other expressions.

[0163] The embodiments in this specification are described in a progressive manner, and each embodiment focuses on the following

[0164] For other differences between the embodiments, reference may be made to the same or similar parts between the embodiments.

[0165] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for a parallel power supply system, characterized in that: A control system applied to a parallel power supply system, the parallel power supply system comprising a plurality of inverters, a plurality of contactors, and an AC busbar, wherein the plurality of inverters are connected in parallel to the AC busbar via the plurality of contactors, a voltage sensor is provided between each contactor and the AC busbar, and a current sensor is provided on a bridge arm of each inverter, the control system of the parallel power supply system comprising a plurality of controllers, each of the controllers being connected in a one-to-one correspondence with each of the inverters, each of the contactors, each of the voltage sensors, and each of the current sensors, wherein the method executed by each of the controllers comprises: Acquiring a first bus voltage collected by the voltage sensor; When the acquired amplitude of the first bus voltage is less than the first preset voltage value, controlling the contactor to close, controlling the timer to start timing, and controlling the amplitude of the output voltage of the inverter to remain at a second preset voltage value within a preset time period; Acquire a first real-time output voltage of the inverter acquired by the voltage sensor, and a first real-time bridge arm current of the inverter acquired by the current sensor; Adjusting or maintaining the phase of the modulation wave of the inverter according to the first real-time output voltage and the first real-time bridge arm current until the timing value of the timer reaches the preset duration; Acquiring a second real-time output voltage of the inverter collected by the voltage sensor; According to the second real-time output voltage and the rated voltage value, the amplitude of the modulation wave of the inverter is adjusted until the amplitude of the output voltage of the inverter is equal to the rated voltage value.

2. The control method according to claim 1, characterized in that: The adjusting or maintaining the phase of the modulation wave of the inverter according to the first real-time output voltage and the first real-time bridge arm current until the timing value of the timer reaches the preset duration includes: Obtaining the active power of the inverter according to the first real-time output voltage, the first real-time bridge arm current and an active power calculation formula; According to the active power, the phase of the modulation wave of the inverter is adjusted or maintained until the timing value of the timer reaches the preset time length.

3. The control method according to claim 2, characterized in that: The method performed by each of the controllers further includes: Acquire a third real-time output voltage of the inverter collected by the voltage sensor, and a second real-time bridge arm current of the inverter collected by the current sensor; Obtaining a voltage error according to the third real-time output voltage and the rated voltage value; Obtaining the reactive power of the inverter according to the third real-time output voltage, the second real-time bridge arm current and a reactive power calculation formula; The amplitude of the modulation wave of the inverter is controlled according to the voltage error and the reactive power.

4. The control method according to claim 3, characterized in that: Before acquiring the first bus voltage collected by the voltage sensor, the method further includes: The first controller controls the corresponding contactor to close, obtains the second bus voltage collected by the corresponding voltage sensor, and samples the obtained second bus voltage to obtain a first sampling value; The remaining controllers obtain a third bus voltage collected by a corresponding voltage sensor, sample the third bus voltage, and obtain a second sampling value. If the second sampling value is not equal to the first sampling value, adjust a voltage sampling coefficient so that a real-time sampling value obtained based on the adjusted voltage sampling coefficient is equal to the first sampling value. The first controller controls the corresponding contactor to open.

5. The control method according to any one of claims 1 to 4, characterized in that: The method performed by each of the controllers further includes: Acquire a fourth real-time output voltage of the inverter collected by the voltage sensor, and a third real-time bridge arm current of the inverter collected by the current sensor; Obtaining a phase and an amplitude of a specific subharmonic voltage and an amplitude of a specific subharmonic current according to the fourth real-time output voltage and the third real-time bridge arm current; Obtaining a harmonic suppression calculation amplitude according to the amplitude of the specific subharmonic voltage and a preset harmonic amplitude; Determine whether the amplitude of the specific subharmonic current is greater than or equal to a preset current threshold; if not, use the harmonic suppression calculated amplitude as the target harmonic suppression amplitude; if so, use the current harmonic suppression amplitude as the target harmonic suppression amplitude; A harmonic suppression wave is obtained according to the phase of the specific subharmonic voltage and the target harmonic suppression amplitude, and a modulation wave of the inverter is adjusted according to the harmonic suppression wave.

6. A control system for a parallel power supply system, characterized in that: The parallel power supply system includes multiple inverters, multiple contactors, and an AC busbar. The multiple inverters are connected to the AC busbar in parallel through the multiple contactors. A voltage sensor is provided between each contactor and the AC busbar, and a current sensor is provided on the bridge arm of each inverter. The control system of the parallel power supply system includes multiple controllers. Each controller is connected to each inverter, each contactor, each voltage sensor, and each current sensor in a one-to-one correspondence. Each controller is used to: Acquiring a first bus voltage collected by the voltage sensor; When the acquired amplitude of the first bus voltage is less than the first preset voltage value, controlling the contactor to close, controlling the timer to start timing, and controlling the amplitude of the output voltage of the inverter to remain at a second preset voltage value within a preset time period; Acquire a first real-time output voltage of the inverter acquired by the voltage sensor, and a first real-time bridge arm current of the inverter acquired by the current sensor; Adjusting or maintaining the phase of the modulation wave of the inverter according to the first real-time output voltage and the first real-time bridge arm current until the timing value of the timer reaches the preset duration; Acquiring a second real-time output voltage of the inverter collected by the voltage sensor; According to the second real-time output voltage and the rated voltage value, the amplitude of the modulation wave of the inverter is adjusted until the amplitude of the output voltage of the inverter is equal to the rated voltage value.

7. The control system according to claim 6, characterized in that: When each of the controllers adjusts or maintains the phase of the modulation wave of the inverter according to the first real-time output voltage and the first real-time bridge arm current until the timing value of the timer reaches the preset duration, it is specifically configured to: Obtaining the active power of the inverter according to the first real-time output voltage, the first real-time bridge arm current and an active power calculation formula; According to the active power, the phase of the modulation wave of the inverter is adjusted or maintained until the timing value of the timer reaches the preset time length.

8. The control system according to claim 7, characterized in that: Each of the controllers is further configured to: Acquire a third real-time output voltage of the inverter acquired by the voltage sensor, and a second real-time bridge arm current of the inverter acquired by the current sensor; Obtaining a voltage error according to the third real-time output voltage and the rated voltage value; Obtaining the reactive power of the inverter according to the third real-time output voltage, the second real-time bridge arm current and a reactive power calculation formula; The amplitude of the modulation wave of the inverter is controlled according to the voltage error and the reactive power.

9. The control system according to claim 8, characterized in that: The first controller is further configured to control the corresponding contactor to close, obtain the second bus voltage collected by the corresponding voltage sensor, and sample the obtained second bus voltage to obtain a first sampled value; The remaining controllers are further configured to obtain a third bus voltage collected by a corresponding voltage sensor, sample the third bus voltage to obtain a second sampling value, and if the second sampling value is not equal to the first sampling value, adjust a voltage sampling coefficient so that a real-time sampling value obtained based on the adjusted voltage sampling coefficient is equal to the first sampling value; The first controller is also used to control the corresponding contactor to disconnect.

10. The control system according to any one of claims 6 to 9, characterized in that: Each of the controllers is further configured to: Acquire a fourth real-time output voltage of the inverter collected by the voltage sensor, and a third real-time bridge arm current of the inverter collected by the current sensor; Obtaining a phase and an amplitude of a specific subharmonic voltage and an amplitude of a specific subharmonic current according to the fourth real-time output voltage and the third real-time bridge arm current; Obtaining a harmonic suppression calculation amplitude according to the amplitude of the specific subharmonic voltage and a preset harmonic amplitude; Determine whether the amplitude of the specific subharmonic current is greater than or equal to a preset current threshold; if not, use the harmonic suppression calculated amplitude as the target harmonic suppression amplitude; if so, use the current harmonic suppression amplitude as the target harmonic suppression amplitude; A harmonic suppression wave is obtained according to the phase of the specific subharmonic voltage and the target harmonic suppression amplitude, and a modulation wave of the inverter is adjusted according to the harmonic suppression wave.

11. An electronic device, characterized in that: include: processor, memory, and communication bus; The communication bus is used to realize the connection and communication between the processor and the memory; The processor is used to execute the control processing program of the parallel power supply system stored in the memory to implement the steps of the control method of the parallel power supply system according to any one of claims 1 to 5.

12. A computer-readable storage medium, characterized in that The readable storage medium stores computer-executable instructions, and when the computer-executable instructions are loaded and executed by the processor, the steps of the control method of the parallel power supply system according to any one of claims 1 to 5 are implemented.

13. A computer program product, characterized in that The method comprises computer executable instructions, which, when loaded and executed by a processor, implement the steps of the method for controlling a parallel power supply system according to any one of claims 1 to 5.

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